Process of sulpnurizing oils



"UNITED STATES PatentedJuly 2, 1940 PATE NT. em

I rRooEss 01+ sunrnuarzme' OILS Harry T. Bennett, Tulsa, kla., assignor to Mid- Continent Petroleum Corporation, Tulsa, Okla, a corporation of Delaware u i No Drawing. Original application January 15,. .1936, SerialNo. 59,311. Divided and this applicationDecemberl, 1939, Serial No. 303,017

2 Claims. (or. 260-1139) Thisinventionj relates to processes of sulphurizing oils, one of theobjects being to provide an effective and economicalprocess of, sulphurizing animal, vegetable. andmineral oils. The present application is a division of an application filed by me on January 15, 1936, Serial No. 59,311.

, .Sulphuriz ed animalj vegetable, and mineral oils have been used ,toa. Considerable extent in I the manufacture of extreme pressure lubricants,

and cutting oils. These sulphurized oilswhen blended with a mineral lubricating oil impart to the blended oil the property of lubricating at extremely high pressures. It is to be understood that high temperatures result in the thickening of the oils, and that prolonged heating even at lower temperatures will also thicken the oil.

The present invention eliminates such thickening and produces a sulphurized oil inthe fluid state required for extreme pressure lubricants.

Heretofore, the cost of preparing sulphurized oils has been objectionable, as it has required relatively long periods of time at high treating temperatures to combine. sulphur with oils. it Moreover, during these relatively long processes at high temperatures,,hydrogen sulphide is evolved and other sulphur products are formed during the reaction.

. As an illustration of the conventional processes employed in sulphurizing oils prior to my invention, I will refer to a treatment wherein lard oil is sulphurized. The lard oil is heated to a temperature of 325 F. with slow agitation ina suitable container. Sulphuris then added to the lard oil at the rateof parts by weight of sulphur to 100 parts of lard oil, and the resultant mixture stirred at 325 F. during the course of four to five hours, or until the sulphur combined with theoil. If it is desired to producea product that will not corrode copper, the

resultant sulphurized mixture is then cooked at 325 F. for an additional hour or more until a bright highly polished copper strip exposed to the mixture shows no corrosion. When it is unnecessary to produce a product that will not.

corrode copper, the final cooking step may be 1 omitted.

I In commercial practice, there would be a very substantial reduction in the cost of sulphurizing oils if the total reacting time of the old processes could be reduced, or if lower treating temperatures could be employed, or if both the time and temperatures were reduced.

I have found that certain compounds, which I term sulphur-combining agents, when added in small quantities to the oil to be sulphurized reduced the reactiontime, or permitted the reaction to take place at a lower temperature.

. Incarrying out my process, the sulphur-combining agent is usuallyadded to the oil at the same time as the sulphur,but may be added just I before orafter the additionof the sulphur without any loss in efficiency. The resultant mixture is agitatedxat the'desired reacting temperature until the sulphur iscornbined with the oil. If

it is desired to produce a product that will not corrode copper, the .s'ulphurized mixture is then cooked until a polished copper strip immersed into the mixture shows nocorrosion.

The invention claimed in the present application is directed to the use of amino sulphur compounds selected from thegroup consisting of diphenyl thiourea, diethyl ammonium diethyl dithiocarbamate and diorthotolyl thiourea.

As an illustration of the effect of these su1- phur-combining agents on the time of reaction, I have compared in the following Table I the i use of difierent quantities of diorthotolyl thiourea with an example where no sulphur-combining agent was employed.

Table I Qlsiglntlilty 0f T t 1 p uro a Sulphur-combining agent combining 23 235 reacting used agent, grams fi and cooking per 100 grams time, hours lard oil F. None 325 6% 1.00 325 3 0. 325 4% 0. 10 325 5 The sulphur-combining agents will also permit a reduction in reaction temperatures, as shown In each of the foregoing tables I have referred to lard oil as the material treated; However, it is not my intention to limit this invention to a specific oil as the various non-drying fatty and mineral oils may be sulphurized in accordance with my process. I

As an illustration of the use of a sulphur-combining agentin sulphurizing amineral oil, I will refer to the treatment of a S. A. E. 30 motor oil with diorthotolyl thiourea. One hundred parts by Weight of the oil were heated with parts of sulphur and two parts of diorthotolyl thiourea and stirred at a temperature of 325 F. for eight made Without departing from the spirit of theinvention, as set forth by the claims.

It is also understood that the invention is not limited to any specific use of the finished sulphurized oil Prior to this invention, compounds of the kind herein described have been employed in the rubber industry, as an aid in vulcanizing the rubber. relate to vulcanization, and the product derived from the invention is a'sulphurized oil, free of constituents resembling rubber.

However, the present invention does not I claim:

1. In the art of sulphurizing fatty and mineral oils, the process of avoiding thickening of the liquid oil which comprises heating a mixture of the liquid oil and sulphur in the presence of an amino sulphur compound selected from the group consisting of diphenyl thiourea, diethyl ammonium diethyl dithiocarbamate, and diorthotolyl thiourea, maintaining the oil at temperatures time of said operation to positively prevent substantial thickening of the oil, and then completing the operation within said limits of temperature and time so as to convert the original liquid oil into a substantially non-thickened sulphurized liquid.

2. In the art of sulphurizing fatty and mineral oils, the process of avoiding thickening of the liquid oil which comprises heating a mixture of the liquid oil and sulphur in the presence of diorthotolyl thiourea, maintaining the oil at temperatures which retain it in a liquid condition during the heating operation, limiting the temperature and time of said operation to positively prevent substantial thickening of the oil, and then completing the operation within said limits of temperature and time so as, to, convert the original liquid oil into a substantially non-thickened sulphurized liquid.

HARRY T. BENNETT. 

